Method and device for locking

ABSTRACT

The present invention concerns a method and a device for locking a disconnecting breaker. During locking of a single-poled or multiple-poled disconnecting breaker, the actuator of the breaker is first locked both electrically and mechanically. When the breaker is in the open position, the distance between the contacts of the breaker comprises the conductor spacing for the isolation function. The electrical and mechanical locking of the actuator is indicated both electrically and mechanically. Subsequently, the link system of the breaker is mechanically locked. The link system is locked in the interlocked position. Locking of the link system is indicated by at least one indicator. Locking of the actuator of the breaker can be controlled manually via a key- and lock device, or remotely.

The present invention concerns a method and a device for locking acircuit breaker and a grounding switch in order to be used as adisconnecting breaker.

THE PRIOR ART

Switching of power lines, cables, power transformers, etc. is done bycircuit breakers. Safety regulations have earlier required adisconnector with a visually open conductor spacing during work on, forexample, a high voltage switch gear. According to the traditionalsolution, a breaker and a disconnector have together ensured that thesection of the equipment where the work is to be carried out isdisconnected. This type of solution requires at least one, and oftentwo, disconnectors with demanding maintenance in order to ensure theircorrect function. Each disconnecting breaker must be correctly installedwith a foundation that requires space and expensive installation time.The present invention is intended to solve the problems described above.The intention is to provide a compact solution, reliable from the pointof view of safety, that is simple to manufacture and cost-effective forthe customer. The construction permits manufacture of the partsaccording to known technology.

SUMMARY OF THE INVENTION

The present invention concerns a method and a device for locking acircuit breaker and a grounding switch to be used as a disconnectingbreaker. The earlier requirement for a visually open disconnector hasbeen replaced according to new regulations by the requirement for areliable indication that a section of the equipment is disconnected. Thedisconnecting breaker replaces a circuit breaker, one or two seriesconnected disconnectors, and means for grounding. The disconnectingbreaker can be either of single-pole type or multiple-pole typedepending on its operating voltage.

During locking of a single-or multiple-poled disconnecting breaker thatincludes a linkage system, known as a “rod system”, for closing andopening operation of the contacts of the breaker, the actuator of thebreaker is first locked electrically and/or mechanically, after whichthe linkage system may also be solidly locked by a mechanical device.When the breaker is in the open position, the distance between thecontacts of the breaker constitutes the conductor spacing of thedisconnecting function, and is large enough to provide the electricalinsulation required for the disconnecting function. The electrical andmechanical locking of the actuator is indicated both electrically and bysuitable indicators (lamp, arrow, etc.). Following the safe locking ofthe breaker in the open position, the grounding switch can be operatedto safely ground one of the breaker terminals.

The locking of the actuator of the breaker is achieved with the aid ofan electromagnetic blocking unit that can be operated with ahand-operated key-and lock device. The blocking unit can in onepreferred embodiment be operated by remote control, e.g. by interruptingthe control power to the actuator. In one preferred embodiment,operation of a hand-operated key- and lock device controls anelectromagnet that locks a blocking package of the actuator of thebreaker by both breaking the operating current to the actuator and bymechanically blocking the actuator. The key device is freed from thelock device following the locking of the actuator of the breaker and isused in a second lock device for mechanical locking of the rod systemwith the aid of a blocking unit. The rod system is locked in the openbreaker position with a second key device and a third lock device. Theblocking of the rod system is indicated by at least one indicator.

According to one embodiment of the device, the second key device is usedwith a fourth lock device in order to free a blocking unit, which makesit possible to move a grounding switch, also known as an earth knife orother earth device. Once the earth knife has been connected to one ofthe breaker contacts, the earth knife is blocked in its connectedposition and locked with the second key device and the fourth lockdevice.

The electrical and mechanical locking of the actuator of the breaker canin one preferred embodiment be achieved with a remote-controlled lockingdevice. The remote-controlled locking of the actuator of the breaker isindicated by electrical and mechanical indicators on the breaker and byindicators on the remote-control unit. In an exemplary embodiment theremote-controlled locking device includes the operation of a blockingdevice for the earth knife, during which operation, movement of theearth knife causes blocking of the rod system. The system according tothe invention is very reliable from the point of view of safety due tothe locking in one preferred embodiment being performed by the exchangeof keys, and due to electrical and mechanical indicators showing inmultiple ways that the breaker is safely locked to prevent anyoperation.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows a sketch of the principle of a disconnecting breaker for athree-phase system.

FIG. 2 shows a sketch of the principle of a disconnecting breaker for asingle-phase system.

FIGS. 3A–3C show an actuator (a), including an electromagnet (b) and anexternal surface (c) for operation of a breaker.

FIGS. 4A–4B show locking of the rod system (a) with a blocking plate andlock (b).

FIG. 5 shows an actuator for an earth knife together with locking of theearth knife with a blocking unit equipped with a lock.

FIGS. 6A–6C show the disconnecting breaker with earth knives (a),blocking device (b) and rotating disk (c) of the locking arrangement ofthe rod system during remote control.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 shows a sketch of the principle of a disconnecting breaker forthree poles. An actuator 10 controls a link system, known as a rodsystem, 20 which connects the poles together and controls the positionsof the contacts 30 of the breaker. The positions of the contacts 30 ofthe breaker are indicated on each pole, for example with a mechanicalarrow 70. An earth knife 40 is controlled by its own actuator 50, whichis in direct electrical connection with the actuator 10 through a cable60 connected between the actuators. When the disconnecting breaker islocked, the actuator 10 is first locked both electrically andmechanically with the aid of an electromagnet 12. After this, the rodsystem 20 of the breaker 30 is locked mechanically. The indication isachieved in one preferred embodiment electrically with a lamp andmechanically with, for example, an arrow. The key-and lock device in onepreferred embodiment is a Castel lock with the associated keys. Whenboth the actuator 10 and the rod system 20 are locked, manual operationand locking of the earth knife 40 according to known technology arepossible.

FIG. 2 shows a sketch of the principle of a disconnecting switch for asingle pole. An actuator 10 controls a link system, also known as a rodsystem, 20 which controls the position of the breaker contacts, e.g. thecontacts 30. The positions of the breaker contacts are indicated, forexample, with a mechanical arrow 70. An earth knife 40 is controlled byits own actuator 50, which is in direct electrical connection with theactuator 10 through a cable 60 connected between the actuators. When thesingle-pole disconnecting switch is locked, the breaker is lockedaccording to the same principle as the three-pole disconnecting switch.

One embodiment of the present invention provides a device for locking acircuit breaker in an open or closed position. In this embodiment, a setof breaker contacts operated by a linking system is in mechanicalcommunication with an actuator. Operation of the actuator, in turn,moves the set of breaker contacts into either an open or closed positionby moving the linking system. The position of each of the set of breakercontacts may be indicated by an indicator, for example, by a mechanicalarrow. In addition to operating the linking system to open or close theset of breaker contacts, the actuator may further contain devices forlocking the linking system in the open or closed position by bothmechanical and electrical means.

Operation of the breaker is controlled by an actuator driving thelinking system. An electromagnet is used to position at least onelocking shackle so as to mechanically prevent operation of a blockingpackage, which mechanically prevents operation of the actuator therebymaintaining the set of breaker contacts in the open or closed position.Electrical locking is achieved by disconnecting the operating current tothe electromagnet operating the locking shackle after positioning thislocking shackle. Therefore, once electrical locking has occurred, thepositioned locking shackle may not be retracted by the electromagnetuntil such current is restored. Electrical locking may be indicated bymechanical and/or electrical indicators present on the actuator, forexample, by illumination of a green lamp and/or a mechanical arrowpointing to a green field.

In one embodiment, the far end of the rod attached to the actuatorextends outward from the outer breaker pole housing when the breakercontacts are in the open position and thus allows for it to bemechanically blocked by a physical connection, for example, to ablocking plate or other similar device to prevent the rod from movingonce the breaker is in the open position. The visible extension of therod upon placing the breaker contacts in the open position furtherserves as an indicator that the breaker is in an open position andallows for closing of the earth knife. The position of the blockingplate can be designed to serve as an indicator that blocking by theblocking plate has been achieved.

FIGS. 3A–3C show the actuator 10 for control of the rod system 20 andthus the position of the contacts 30. The actuator 10 includes ablocking package 11 that solidly prevents mechanical movement of theactuator 10 and thus also any operation of the breaker contacts. Theblocking package 11 prevents operation of the breaker 30 together withan electromagnet 12 equipped with a mechanical locking shackle 13 orequivalent device. The mechanical locking shackle 13 or equivalentdevice mechanically prevents any unintended movement of the blockingpackage. When a first key 18 is turned in the lock 14, the electromagnet12 releases, and operating current to the blocking package 11 isinterrupted. The blocking package 11 is locked by breaking its operatingcurrent and by turning off the operating current to the electromagnet 12equipped with the mechanical locking shackle 13. Under the conditionthat the breaker is in the OFF position, the shackle 13 is releaseddownwards and mechanically blocks movement of the blocking package fromthe OFF position to the ON position. Indication that locking of theactuator is achieved may, for example, be realized by the lighting of agreen lamp 19 on the external surface of the actuator and by amechanical arrow 16 pointing towards a green field of a mechanical arrow16 inside the actuator. An auxiliary contact 17 provides electricalinterruption or closing of a signal, which indicates the position of thebreaker. When the breaker is OFF and the actuator is locked, a signal issent via the auxiliary contact 17 and the cable 60 to the actuator 50 ofthe earth knife. This is one of the conditions that must be satisfied ifmovement of the earth knife is to be possible. If the breaker is in theON position when the actuator is locked, the breaker can in onepreferred embodiment be automatically switched over to the OFF position.In one preferred embodiment the actuator of the breaker can be lockedwith the breaker in the ON position. The indicator 70 then indicatesthat the breaker is in the ON position. Movement of the earth knife isnot possible in this condition since this requires a signal via theauxiliary contact 17 and the cable 60 to the actuator of the earthknife.

FIGS. 4A–4B show part of a link system, known as a rod system, 20 foroperation of the contacts 30 of the breaker. The rod system 20 isequipped with a moving part 21 that is in an inner position when thebreaker is ON and an outer, visible position when the breaker is OFF.FIG. 4B shows an exemplary blocking plate 23. As can be seen withrespect to FIG. 4B, a hole in the blocking plate 23 includes a firstregion 202 large enough to permit the moving part 21 to move or rotatefreely, and a second region 204 that is smaller than the first region202. As can be seen from FIG. 4B, the second region 204 is large enoughto receive the moving part 21 when the moving part 21 is rotated 90degrees to align with the second region 204, and will prevent the movingpart 21 from rotating when the moving part 21 is in the second region204, e.g. after the blocking plate 23 has been pushed in a sidewaysdirection. By turning the first key 18 in a second lock 22, manualmovement of a blocking plate 23, or other blockage device, is madepossible. The blocking plate 23 is pushed in a sideways direction andlocked in place with a second key 24 in a third lock 25 such that themoving part 21 and thus the rod system 20 are locked into positionscorresponding to open breaker. The locking of the rod system can beindicated with, for example, an arrow.

FIG. 5 shows the earth knife 40 with its actuator 50. The position ofthe earth knife is controlled by a link system 51.

FIGS. 6A–6C show the design of the rod system when remote-controlledlocking is used. Movement of the earth knife involves movement of theblocking plate 23 via a rotatable disk 80.

1. A disconnecting breaker comprising: a) at least one set of breakercontacts; b) an actuator mechanically connected to said at least one setof breaker contacts by a linking system, wherein said actuator controlsthe position of the breaker contacts between a closed position-and anopen position; and c) a mechanical a first lock that blocks the movementof the linking system and maintains said at least one set of breakercontacts in the open position; and d) a second lock that locks theactuator to prevent actuator control of the breaker contacts, whereinthe second lock includes an electrical lock that interrupts controlpower to the actuator and prevents actuator control of said at least oneset of breaker contacts.
 2. The disconnecting breaker of claim 1 whereinthe second lock includes: an electromagnetically operated lockingshackle capable of mechanically locking the second lock to preventactuator control of said at least one set of breaker contacts.
 3. Thedisconnecting breaker of claim 2 wherein the second lock includes: anelectrical lock that interrupts control power to the electromagnet ofthe locking shackle.
 4. A disconnecting breaker comprising: a) at leastone set of breaker contacts; b) an actuator mechanically connected tosaid at least one set of breaker contacts by a linking system, whereinsaid actuator controls the position of the breaker contacts between aclosed position and an open position; and c) an electromagneticallyoperated blocking package capable of mechanically locking the actuatorto prevent actuator control of said at least one set of breakercontacts; and d) an electrical lock that interrupts control power to theactuator and prevents actuator control of said at least one set ofbreaker contacts.
 5. The disconnecting breaker of claim 4 comprising: anelectrical lock that interrupts control power to the blocking package.6. The disconnecting breaker of claim 5, comprising anelectromagnetically operated locking shackle capable of mechanicallylocking the blocking package.
 7. A disconnecting breaker comprising: a)at least one set of breaker contacts; b) an actuator mechanicallyconnected to said at least one set of breaker contacts by a linkingsystem, wherein said actuator controls the position of the breakercontacts between a closed position and an open position; and c) anelectrical lock that interrupts control power to the actuator andprevents actuator control of said at least one set of breaker contacts;and d) a mechanical lock that blocks the movement of the linking systemand maintains said at least one set of breaker contacts in the openposition.
 8. The disconnecting breaker of claim 7 comprising: anindicator indicating that the actuator is electrically locked.
 9. Thedisconnecting breaker of claim 7, wherein said disconnecting breakerincludes multiple sets of breaker contacts.
 10. The disconnectingbreaker of claim 7 wherein a distance between the contacts in the openposition comprises a conductor spacing for a disconnection function. 11.The disconnecting breaker of claim 7 comprising: an indicator indicatingthat the linking system is mechanically locked.
 12. The disconnectingbreaker of claim 7 comprising: an electromagnetically operated blockingpackage capable of mechanically locking the actuator to prevent actuatorcontrol of said at least one set of breaker contacts.
 13. Thedisconnecting breaker of claim 12 comprising: an indicator indicatingthat the actuator is mechanically locked.
 14. The disconnecting breakerof claim 12, wherein the blocking package is operated by remote control.15. The disconnecting breaker of claim 12 comprising: an electrical lockthat interrupts control power to the blocking package.
 16. Thedisconnecting breaker of claim 15, comprising an electromagneticallyoperated locking shackle capable of mechanically locking the blockingpackage.
 17. The disconnecting breaker of claim 7, comprising a handoperated first key and lock device to achieve electrical and mechanicallocking of the actuator.
 18. The disconnecting breaker of claim 17wherein the operation of the first key and lock device releases anelectromagnetic locking shackle that locks a locking package on theactuator.
 19. The disconnecting breaker of claim 17, wherein theoperation of the hand operated key and lock device causes the breaker tochange from said closed position to said open position.
 20. Thedisconnecting breaker of claim 17, comprising a second lock deviceoperated by the first key for mechanical locking of the linking system,wherein locking of a blocking plate and linkage system is achieved by asecond key device within a third lock device.
 21. The disconnectingbreaker of claim 20, comprising an actuator for an earth knife whichallows for connection of the earth knife to at least one of the breakerterminals per pole, thereby earthing at least one of the terminals. 22.The disconnecting breaker of claim 21 wherein the fourth lock device islocked with said second key device after said connection.
 23. Thedisconnecting breaker of claim 21, comprising a fourth lock device forlocking the earth knife in either an earthed or an unearthed position.24. A method for locking a disconnecting breaker with at least one setof breaker contacts comprising: a) activating an actuator mechanicallyconnected to said at least one set of breaker contacts by a linkingsystem, wherein said actuator controls the position of the breakercontacts between a closed position and an open position; b) engaging afirst lock that blocks the movement of the linking system and maintainssaid at least one set of breaker contacts in the open position; and c)engaging a second lock that locks the actuators, wherein the second lockcomprises an electrical lock that interrupts control power to theactuator and prevents actuator control of said at least one set ofbreaker contacts.
 25. Method according to claim 24, wherein the firstlock includes a mechanical lock that prevents the movement of thelinking system.
 26. Method according to claim 24, comprising: indicatingthe locking of the linking system using at least one mechanicalindicator.
 27. The method of claim 24, wherein the first lock and theelectrical lock are engaged via remote control.
 28. Method according toclaim 24, wherein the second lock includes an electrical and amechanical locking which locks the actuator and prevents movement of thelinking system.
 29. Method according to claim 28, wherein the electricaland mechanical locking of the actuator is carried out with the breakerin the open position, whereby a distance between the contacts comprisesa conductor spacing for a disconnection function.
 30. Method accordingto claim 28, wherein the first lock includes a mechanical lock thatprevents the movement of the linking system.
 31. Method according toclaim 28, comprising: indicating the electrical and mechanical lockingusing an electrical indicator and a mechanical indicator.
 32. Methodaccording to claim 28, wherein the electrical and mechanical locking ofthe actuator is achieved by means of a hand-operated first key- and lockdevice.
 33. Method according to claim 32, wherein the operation of thefirst key- and lock device releases an electromagnetic locking shacklethat locks a blocking package on the actuator.
 34. Method according toclaim 32, wherein the electrical and mechanical locking of the actuatoris carried out with the breaker in the closed position, whereby thehand-operated first key- and lock device achieves an automatic change ofthe breaker from said closed position to said open position.
 35. Methodaccording to claim 32, wherein the first key of said first key- and lockdevice is freed from said key- and lock device following the locking ofthe actuator and is used in a second lock device for mechanical lockingof the linking system with the aid of a blocking plate, which locking isachieved by a second key device with a third lock device.
 36. Methodaccording to claim 35, wherein an actuator for an earth knife orequivalent earth device is unlocked from a fourth lock device with saidsecond key device so as to allow connection of the earth knife to thebreaker, and is locked with the second key device and the fourth lockdevice after said connection.
 37. Method according to claim 35, whereinthe electrical and mechanical locking of the actuator of the breaker iscarried out with the breaker in the closed position, whereby the firstkey device is blocked into the lock device following the locking of theactuator.
 38. Method according to claim 28, wherein the electrical andmechanical locking of the actuator of the breaker is achieved by meansof a remote control.
 39. Method according to claim 38, wherein theremote-controlled electrical and mechanical locking of the actuator ofthe breaker is carried out with the breaker in the open position,whereby the distance between the contacts comprises a conductor spacingfor a disconnecting function.
 40. Method according to claim 39, whereinsaid locking includes mechanical movement of a blocking device for anearth knife, after which movement of the earth knife involves mechanicallocking of the linking system.